I think IDK means that they melt it in a vacuum, using magnetic induction heating to do the actual heating of the Tantalum.

Induction heating - Wikipedia, the free encyclopedia
{Induction heating is the process of heating an electrically conducting object (usually a metal) by electromagnetic induction, where eddy currents (also called Foucault currents) are generated within the metal and resistance leads to Joule heating of the metal}

Thanks for that, I probably wouldn't have looked it up otherwise.
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[After editing] I definatly would not have found out about 'Induction brazing' without this thread. I had wondered how they got the Gold solder to melt when welding some electrical parts shut. Like SAW devices & CPU's.